If you dare I can describe the safety protocols in our club Cyrnéa in Lyon, France.
First of all we have to have our own professionally licensed life-guard doing the surveillance exclusively for us (even if there are several other life-guards in the pool on duty). And since twice a week we happen to have two groups of freedivers training concurrently, where one train statics in a kids pool, while the other dynamics in the swimming pool, we have to have a separate life-guard for each group.
Then, there is the instructor, who directs the training. Again each group has his own instructor, and the instructor must not train with the others. (though I admit, in some cases, at the more experienced group, there are sometimes some violations of this rule). The instructor must have a valid certificate for freediving training (FFESSM) and for freediving cpr/rescue (RIFAA).
Then, in each group, people work in smaller units of 2-3 freedivers, where they are obliged to watch their buddies. At longer dives, or at longer static times, they dive individually (not in the same or overlapping time), so that there is always at least one of them on the surface who watches the others all the time, incl. ~30s after surfacing). At attempts closer to PB, or at other dives with higher risk, full safety just like at a competition is provided - two safety divers with floats, following the freediver and assuring his safety.
Then we also do regular accident simulation drills - one of the freedivers (without previously telling to anyone, except of the instructor) simulates a BO during a swim - dropping at the bottom and releasing some air, and we then watch whether all react as they should. We simulate the complete worse-case rescue, including using of a defibrillator and calling the ambulance. All that (including the rescue times) is then logged into a protocol book that can be review by the pool management.
I should also mention that the policy of our club (unlike at some others) is that the trainings must be samba and blackout free. If samba happens to a freediver (which is rather rare), it is the end of the training session for him.
Also, all trainings are based on sub-maximal performances. When we do maximal attempts, the session is organized in the same way as a competition, with all the safety in place, and with the life-guard on a higher alert, with CPR equipment ready at hand.
All this may seem perhaps too restrictive, and some people would tell that with such submax training no good results can be achieved, but the results of the club are not at all that bad - only last year we gained around 50 medals in competitions, and have a French national champion in static apnea, so it is not too bad, I think.
EDIT: also, this belong into the protocol that you could pass to the pool magement too - have clear club statuses, that each member has to agree to, and to sign before being accepted. And make sure that all the safety proceedings are well described there. I could give you our registration form, but it is in French, and I am really lazy to translate it. We also require that our members have an up-to-date medical certificate valid for freediving, valid license of the FFESSM federation (which includes insurance), so having something like that in place may help when dealing with the pool managment too.
